New TG585v7 - which firmware is recommended?

[#1]

My current TG585v7 has been dropping connections lately and, worse still, seemingly not managing to recover.
Whilst it is still accessible from the LAN via telnet (not via the web interface) even a system reboot doesn't recover it. Instead I have to physically power cycle it and so it's not like I can even set a script running to monitor it and issue a reboot command via telnet if it freezes.
So, I've picked up another TG585v7 off eBay to see if it fairs any better - I don't know which ISP it came from, nor if it's tied to another user (are they?) but either way I was going to reflash its firmware and reset the config. Looking at the available Plusnet firmwares I see I've effectively got the choice between v8.2.6.5 and v8.2.23.0. I'm currently using the former, but am a fan of increasing revision numbers(!) so wondered if it is recommend to use what is presumably a newer firmware? Less bugs perhaps, or just different? I note the caveat about PPTP VPN issues with v8.2.23.0 however that is not an issue for me.
Anyway, if someone can advise I'd appreciate it. If there's anything else you're aware of that I might not be that too would be welcome.
Mathew
P.S. On a related note, will a backup of the current config via the web interface backup everything i.e. including any parameters that I've set via telnet (that weren't configurable via the web interface) such as getting the WAN to respond to ICMP? Can/should this only be done if I stick with the same firmware version that I'm currently running?

[#2]

The latest software for the TG585v7 is, in fact, 8.2.6.5. The version identified as 8.2.23.0 is incorrectly numbered (I've no idea what the correct number should be).

[#3]

Ah okay - that answers that one then! Thanks!
Do you happen to know about the backing up of config? If there are doubts as to its completeness I may have to dig through old notes to see what I'd changed through the backend...

[#4]

I'd be inclined not to rely on a saved configuration being restorable after software update - best to be prepared. I'd expect the saved configuration to include all settable parameters, but maybe I'm just being optimistic.
I'm not aware of any incompatibility of such information between versions, but that doesn't mean there aren't any.
I guess that's a long way of saying "don't know".

[#5]

I've never tried with a TG585 but saving/restoring with different f/w versions on a TG585n isn't very reliable.

[#6]

Thanks both. I'll stick to v8.2.6.5, see if the saved config has worked and take it from there.
Ideally I'd buy a new, better, router but we're expecting FTTC in December and so would rather hold out for that before buying any new kit.... (assuming the date doesn't slip of course)
I suppose I could buy something that'll be pluggable into a bare modem when the time comes...